Oda favors Luffy. After the time skip the manga has almost become Luffy piece with entire arcs with half the crew but Luffy. Then he favors Zoro a lot too but still less than Luffy andbthat is why we had arcs like WCI, Impel down and Marineford without him uet now he is shining on the roof top even more than Luffy (for now). Then there is Sanji he has been a sort of mix of a badass and comedy character (this also matches with the other YC2) and that ruins his reputation in the eyes of whow ants him to fight at the same level (or almost) as Luffy and Zoro yet post time skip things changed a bit. The nose bleed gag was brought too far in Fishman island and that was already a clue, he was used to hype Vergo, a mere underling of a character Luffy surclassed with G4 (not to mention how Zoro walked Pica, the par of Vergo, or how Law oneshotted Vergo). Then WCI was good but also bad for Sanji, at least for "Sanji the fighter" while now, continuing the trend, it seems he is almost left behind Jinbe while Luffy and Zoro are shining on the roof top as the top fighters of the alliance (along with Kidd, Killer and Law).